Electrode discharge control for surgical apparatus



Marchl8f1'958 J. DEGELMAN 2,827,056

ELECTRODE DISCHARGE CONTROL FOR SURGICAL APPARATUS Filed June 21, 1955 a{Zoe/wwe/& m e We)! dug];

United States PatentO ELECTRODE DISCHARGE CONTROL FOR SURGICAL APPARATUSJohn Degelman; HarvanL Massi, assignorof one-half to Thomas-H;Ballantine, Jix, Dedham, and one-half: to John H. Drew, Framingham,Mass.

ApplicationJune 21,1955; SerialjNo. 516,927

Claims. ((31.128-422) This inventionrelates to apparatus forcontrollingthe discharge'of current from -an electrode into abody whichis moreor less conductive. More particularly the-invention relates toapparatus fordischarging highfrequency current to a wound in ahuman'bodyfor the purpose'of cauterizing the wound Heretofore the flowofcurrent to such an electrode has been controlled by a manual switch onthe electrode itself or a foot switch-controlled'by-the operator.Neither controlhas been satisfactory because they both interfere withthe work of the operator which is often of a delicate nature as, forexample,- inthe case of a surgeon cauterizing a wound; Moreover a switchon the electrode often interferes with the facile operation of theelectrode;

Objects of the present invention are-to provide a control whicheliminates all manual controls,- which automatically supplies dischargecurrent when: the electrode is' presented to-the body, andwhich requiresonly a single conductor leading to the'electrode.

According to the present invention the apparatus comprises a workcircuit for supplying alternating current to the body when the electrodeis presented tothe body, and a control circuit including a source ofdirect current and control means responsive to the aforesaid sourceforinitiating flow of alternating current to the work circuit when thecontrol circuit is closed, the aforesaid circuits having a commonportion including saidbody and electrode, whereby the control circuit isclosed by touching the body with the electrode.

In a more specific aspect the apparatus comprises an electronic devicehaving a control electrode which puts the device in non-conductingcondition at one potential and in conducting condition at anotherpotential, and a control circuit including the aforesaid body andelectrodes for changing the potential of the control electrode from thefirst to the second of the aforesaid potentials when the dischargeelectrode is presented to the body, whereby current in the work circuitis initiated when the discharge electrode is presented to the body.Preferably the electronic device comprises a triode or transistor havingdirect current bias means for normally holding the control electrode ata potential to maintain the device in non-conductive condition. Thecontrol circuit should be connected to the work circuit at a pointbetween the source of alternating current and the discharge electrode sothat the electrode requires only one conductor. Also the apparatusshould have an inductor in the control circuit between the twoelectrodes and a condenser in the work circuit between the source ofalternating current and a point at which the control circuit isconnected to the work circuit. Preferably the electronic device is ofthe type having an output circuit for controlling the supply of currentto the work circuit and an input circuit including the aforesaid bodyand electrode for changing the potential from inoperative to operativewhen the discharge electrode is presented to the body.

For the purpose of illustration a typical embodiment 2,827,056 PatentedMar. 18 1958 2 of the 'invention is shown-in the accompanying drawingsinwhichzthe figure is alcircuitdiagram.

The-particular embodiment illustrated in the drawingcomprisesaworkcircuit 12:supplied from any suitable source ofalternating current and containing a switch 3; acondenser 4,1 theaforesaid discharge electrode 6 and a support- Tfor theaforesaid body towhich the. electrode 6:is tobe presented. While'thessupport 7 may beconnectedadirectly to therside 2 of the .work circuit, as illus trated'tboth the conductor. 2; and the support 7 are grounded; The=switch3 isclosed by means of a relay-8 connectedstotthe, plate 9 ofi-a triode 10comprising acathode 11' and; a grid-: 12,. the..cathode being connectedto the; side-2., of; the work circuit. The. grid 12 isbiasedby:means-.,-of-a directscurrent source C througha cone ductor 13and,-two' resistors-1,4 and. 16. Connected acrossithe workcircuit isa.bridge circuit-17 containing induetance 18-, and. capacitance 19,- theconductor 17 being connec ted to 13 intermediate the. inductance. andcapacitance. The capacitance 4v prevents the. flow. of direct-current;back tothe source of, alternating current and the-,inductance;1 8-blocks the flow of alternatingcurrent through the control circuit, Ahigh resistance 15 may also, beincluded in conductor 13- asillustrated.

For cauterizing wounds the discharge current may have a. frequency'of:the, order of; one megacycle or more and a'potential-of the order of onethousand volts, in which casethe value-of the resistors, 14 and 16 maybeof the QIder of ten; million ohms. each. The value of C.. should beapproximately twicethe voltage required to effectively cut off the flowof plate current in the triode, fo r examplefortyvolts.

Normally no substantial amount ofcurrent flows through the triodebecauseof the bias produced by the sourceC However,- when the electrodedis grounded, by contact withv a conducting body resting on the.grounded support 7, the potential drop between plate 9, and cathode 11.is greatly reduced. This results in the energization of relay 8 whichcloses the switch 3, thereby automatically supplying alternating.current to the electrode 6. v V i From the foregoing itwill be evidentthat the present invention eliminates manual switches and initiates theflow of discharge current automatically the moment the dischargeelectrode touches. the patient or other grounded body which is more. orless conducting. It will also be evident that the apparatus requiresonly a single conductor leading to the discharge electrode, therebyfacilitating the use of the electrode. When the body being operated onis a human bodyit may be grounded merely by resting on the groundedsupport 7 However, in this case the body is preferably rested on a morecomfortable support and grounded by means of one or more electrodes heldagainst the body by suitable means.

When operating on a human body, particularly in th region of the brain,it is important not to impart a stimulus, and this is accomplished withthe present invention by employing high frequency current in the workcircuit and, in'the control circuit, low potential and high resistanceso that there is no substantial direct current flow through the body.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. For discharging current into a human body from a discharge electrode,surgical apparatus comprising a work circuit for supplying current tothe electrode, and means for controlling the supply of current to thework circuit, said means comprising an electronic device having a contol e ectrod which p the ev e in n-c nduc ing condition at one potentialand in conducting condition at another potential and a control circuitincluding said body and electrodes for changing the potential of saidcontrol electrode from the first to the second of said potentials whenthe discharge electrode is presented to the body, whereby current in thework circuit is initiated when the discharge electrode is presented 'tothe body.

2. For discharging current into a human body from a discharge electrode,surgical apparatus comprising a work circuit for supplying current tothe electrode, and means for controlling the supply of current to thework circuit, said means comprising an electronic device havmg a controlelectrode, bias means normally holding the control electrode at apotential to hold said device nonconductive and a control circuitincluding said body and electrodes for altering the potential of saidcontrol electrode when the discharge electrode is presented to the bodythereby to cause said device to conduct.

3. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, and means for controlling thesupply of current to the work circuit, said means comprising anelectronic device having a control electrode which puts the valve innon-conducting condition at one potential and in conducting condition atanother potential, direct current bias means normally holding thecontrol electrode at said first potential, and a control circuitincluding said body and electrodes for changing the potential of saidcontrol electrode from the first to the second of said potentials whenthe discharge electrode is presented to the body, and an inductor in thecontrol circuit between said electrodes.

4. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, and means for controlling thesupply of current to the work circuit, said means comprising anelectronic device having a control electrode which puts the valve innon-conducting condition at one potential and in conducting condition atanother potential, direct current bias means normally holding thecontrol electrode at said first potential, and a control circuitincluding said body and electrodes for changing the potential of saidcontrol electrode from the first to the second of said potentials whenthe discharge electrode is presented to the body, the control circuitbeing connected to the work circuit at a point between the source ofalternating current and the discharge electrode so that the electroderequires only one conductor, and a condenser in the work circuit betweenthe source of alternating current and said point. 7

5. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, and means for controlling thesupply of current to the work circuit, said means comprising anelectronic device having a control electrode which puts the device innon-conducting condition at one potential and in conducting condition atanother potential, direct current bias means normally holding thecontrol electrode at said first potential, and a control circuitincluding said body and electrodes for changing the potential of saidcontrol electrode from the first to the second of said potentials whenthe discharge electrode is presented to the body, the control currentbeing connected to the work circuit at a point between the source ofalternating current and the discharge electrode so that the electroderequires only one conductor, and an inductor in the control circuitbetween said electrodes.

6. For discharging current into a human body from a discharge electrode,surgical apparatus comprising a work circuit for supplying current tothe electrode, an electronic device having an output circuit forcontrolling the supply of current to said work circuit and a controlelectrode having an inoperative potential at which the potential acrossthe output circuit prevents supply of current to the work circuit and anoperative potential at which the potential across the output circuitsupplies current to the work circuit, and an input circuit includingsaid body and electrodes for changing said inoperative potential tooperative potential when the discharge electrode is presented to thebody, whereby current in the supply circuit is initiated when thedischarge electrode is presented to the body.

7. For discharging current into a human body from a discharge electrode,surgical apparatus comprising a work circuit for supplying current tothe electrode, an electronic device having an output circuit forcontrolling the supply of current to said work circuit and a controlelectrode having an inoperative potential at which the potential acrossthe output circuit prevents supply of current to the work circuit and anoperative potential at which the potential across the output circuitsupplies current to the Work circuit, bias means for supplying saidpotentials, and an input circuit including said body and electrodes forchanging said inoperative potential to operative potential when thedischarge electrode is presented to the body, whereby current in thesupply circuit is initiated when the discharge electrode is presented tothe body. a

8. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, an electronic device having anoutput circuit for controlling the supply of current to said'workcircuit and a control electrode having an inoperative potential at whichthe potential across the output circuit prevents supply of current tothe work circuit and an operative potential at which the potentialacross the output circuit supplies current to the work circuit, directcurrent bias means for supplying said potentials, and an input circuitincluding said body and electrodes for changing said inoperativepotential to operative potential when the dis charge electrode ispresented to the body, and an inductor input circuit between saidelectrodes.

9. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, an electronic device having anoutput circuit for controlling the supply of current to said workcircuit and a control electrode having an inoperative potential at whichthe potential across the output circuit prevents supply of current tothe work circuit and an operative potential at which the potentialacross the output circuit supplies current to the work circuit, directcurrent bias means for supplying said potentials, and an input circuitincluding said body and electrodes for changing said in operativepotential to operative potential when the discharge electrode ispresented to the body, the output current being connected to the workingcircuit at a point between the source of alternating current and thedischarge electrode so that the electrode requires only one conductor,and a condenser in the working circuit between the source of alternatingcurrent and said point.

10. For discharging alternating current into a human body from adischarge electrode, surgical apparatus comprising a work circuit forsupplying the current to the electrode, an electronic device having anoutput circuit for controlling the supply of current to said workcircuit and a control electrode having an inoperative potential V atwhich the potential across the output circuit prevents supply of currentto the work circuit and an operative potential at which the potentialacross the outputcircuit supplies current to the work circuit, directcurrent bias means for supplying said potentials, and an input circuitincluding said body and electrodes for changing said inoperativepotential to operative potential when the discharge electrode ispresented to the body, the control References Cited in the file of thispatent current being connected to the supply circuit at a point UNITEDSTATES PATENTS between the source of alternating current and theelectrode so that the electrode requires only one conductor, 2,251,277Hart et Aug 51 1941 and an inductor in the control circuit between said5 2293851 Rogers 1942 dectrodes. 2,379,837 Stahrner July 3, 19452,443,232 Fagen June 15, 1948 2,526,597 Winslow Oct. 17, 1950

